CHAMPION Z9Y SPARK PLUG

Function and technical context

The spark plug is the component responsible for generating the electrical spark that ignites the air-fuel mixture in the combustion chamber of the outboard engine. Integrated into the ignition system of two- and four-stroke engines, it supports continuous cycles of high electrical voltage, high temperatures and internal pressures that require maximum reliability. When the spark plug deteriorates, the ignition becomes irregular, causing loss of power, increased fuel consumption and inability to start. In Yamaha engines, keeping the spark plug in optimal condition is essential to guarantee clean, efficient and reliable combustion on every outing to the sea.

When to replace this part?

The most common symptoms of a worn spark plug include difficulty starting the engine when cold, jerking or misfiring at idle, uneven acceleration, and higher than usual petrol consumption. As a general rule for outboard engines, it is recommended to check and replace spark plugs every season or every 100 hours of operation, whichever comes first, since the marine environment accelerates their deterioration. Changing the spark plug preventively at the beginning of each campaign is the simplest and most economical measure to avoid a stoppage at sea due to ignition failure.

Equivalent manufacturer part numbers